Cisco: Kernel panic caused by RCU stall while accessing flash file system

Summary: An MDS Supervisor-4 module resets without warning.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.

Symptoms

An MDS Supervisor-4 module resets while accessing a flash file system.
The show system reset-reason shows the reason as a kernel panic:

Reason: Kernel Panic

 

The show system internal kenel nvram-messages previous command has the following messages: 1.A warning for "d_shrink_del" 2. "rcu_sched self-detected stall" type of signature line and "t=" value is 2100 or greater (the CPU number and PID are not relevant)

[850772.912879 <3>] WARNING: CPU: 3 PID: 11665 at ... d_shrink_del+0x30/0x73()
...
[850793.913314 <3>] INFO: rcu_sched self-detected stall on CPU { 3}  (t=2101 jiffies g=12138660 c=12138659 q=39875)
...
[850793.917818 <3>] Kernel panic - not syncing: RCU self stall taking too long

 

Cause

Cisco bug CSCwj03301This hyperlink is taking you to a website outside of Dell Technologies.
This issue may apply only to Cisco MDS NX-OS releases earlier than release 9.4(1).
This issue may apply only to Cisco MDS Supervisor-4 platforms.

 

Resolution

Fix:
Upgrade to NX-OS code 9.4.1 or higher

 

Affected Products

Connectrix MDS-Series, Connectrix MDS-9706, Connectrix MDS-9706-V2, Connectrix MDS-9710, Connectrix MDS-9710-V2, Connectrix MDS-9718, Connectrix MDS-9718-V3, Connectrix MDS-Series Firmware 8.X, Connectrix MDS-Series Firmware 9.X
Article Properties
Article Number: 000222207
Article Type: Solution
Last Modified: 20 Feb 2024
Version:  1
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